Blockstream Esplora API

Free Blockstream Esplora API with no key: Bitcoin blocks, transactions, addresses, UTXOs and mempool data. Open source and self-hostable. Tested example.

No API key requiredCORS enabledHTTPSFree tier

Endpoint tested and returned HTTP 200 on 20 Aug 2026

What is the Blockstream Esplora API?

Blockstream's Esplora API is a free, key-free Bitcoin blockchain explorer API providing blocks, transactions, address balances, UTXO sets and mempool state, with the entire stack open source and self-hostable.

Esplora is the API behind Blockstream's block explorer, and it is fully open source — which matters for Bitcoin applications where trusting a third party for chain data is a real consideration. You can run your own instance against your own node.

The endpoints are refreshingly direct: some return a bare number as plain text rather than a JSON object. `/blocks/tip/height` returns just the integer, which is efficient but will break a client that assumes every response is JSON.

Quick facts

Base URL: https://blockstream.info/api
Authentication: No API key required on the public instance.
Rate limit: No published hard limit; heavy users should self-host.
Pricing: Free and open source.
CORS: Enabled — callable directly from browser JavaScript
Official docs: Read the docs

How to use the Blockstream Esplora API

Every request below was executed against the live API on 20 Aug 2026, and the response shown is the real body it returned — not an illustration.

1. Get the current Bitcoin block height

GET https://blockstream.info/api/blocks/tip/height

curl

curl 'https://blockstream.info/api/blocks/tip/height'

JavaScript (fetch)

const res = await fetch("https://blockstream.info/api/blocks/tip/height");
if (!res.ok) throw new Error(`Request failed: ${res.status}`);
const data = await res.json();
console.log(data);

Python (requests)

import requests

res = requests.get("https://blockstream.info/api/blocks/tip/height", timeout=20)
res.raise_for_status()
print(res.json())

Response — HTTP 200

Parameters

Parameter	Type	Required	Description
`blocks/tip/height`	path	Optional	Current chain tip height — returns a bare number. `blocks/tip/height`
`block/<hash>`	path	Optional	Block details by hash. `block/000000...`
`address/<addr>`	path	Optional	Address balance and transaction stats. `address/bc1q...`
`address/<addr>/utxo`	path	Optional	Unspent outputs for an address. `utxo`
`tx/<txid>`	path	Optional	Transaction details. `tx/abc123`

Response fields

(tip/height)integer: A bare integer, not JSON — the current block height.
(address) chain_statsobject: Confirmed funded and spent totals for the address.
(address) mempool_statsobject: Unconfirmed activity for the address.
(tx) status.confirmedboolean: Whether the transaction is confirmed.
(tx) vin / voutarray: Transaction inputs and outputs with values in satoshis.
(block) height / timestamp / tx_countinteger: Block metadata.

What you can build with the Blockstream Esplora API

Build a Bitcoin block explorer or wallet backend
Monitor an address for incoming payments
Verify transaction confirmations
Track chain tip height for sync status

Common errors and how to fix them

JSON parse error on tip/height

That endpoint returns a bare number as plain text.

Fix: Not every Esplora endpoint returns JSON — read the response as text for scalar endpoints.

Values seem enormous

Amounts are in satoshis.

Fix: Divide by 100,000,000 to get BTC.

Rate limiting on the public instance

Shared infrastructure.

Fix: Self-host Esplora against your own Bitcoin node for production use.

Blockstream Esplora API — frequently asked questions

Is the Blockstream API free?

Yes, the public instance is free with no API key, and the whole Esplora stack is open source and self-hostable.

Why does the block height endpoint fail to parse as JSON?

It returns a bare integer as plain text. Several Esplora endpoints return scalars rather than JSON objects — read them as text.

Should I use the public instance in production?

For a real Bitcoin application, self-host Esplora against your own node. That removes both the rate limit and the trust dependency on a third party for chain data.

What units are amounts in?

Satoshis — the smallest Bitcoin unit. Divide by 100,000,000 to get BTC.

Tools that pair with this API

JSON Formatter

Format, beautify and minify JSON online with 2-space, 4-space or tab indentation. Sort keys alphabetically and catch syntax errors instantly — free and private.

Unit Converter

Convert between units of length, weight, temperature, area, volume, speed, time and data storage instantly, with a swap button and common conversion tables.

Alternatives to Blockstream Esplora API

If Blockstream Esplora does not fit, these finance & crypto apis cover similar ground. Every one was called before publishing, and each links to its own reference page with a working curl command and the response it returned.

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Frankfurter	Free currency exchange rate API with no key, built on European Central Bank data. Latest and historical rates, time series and conversion. Tested curl example.	No key	Yes	19 Aug 2026
US Bureau of Labor Statistics	Free Bureau of Labor Statistics API with no key on v1: unemployment rate, CPI, payrolls and thousands of US labour series by series id. Tested example and live response.	No key	Yes	21 Aug 2026
Brønnøysund Register (Norway)	Free Brønnøysund Register Centre API with no key: search every Norwegian company by name or organisation number, with address, industry code, employees and name history.	No key	Yes	21 Aug 2026

All Finance & Crypto APIs

Blockstream Esplora is an independent third-party service and is not affiliated with ByteTools or ByteVancer. Details on this page were verified on 20 Aug 2026; always check the official documentation before relying on this API in production, as terms and limits can change.